This invention concerns in general containers made of crystal for containing food products or drinks and especially, but without being a restriction, for spirits.
It is well known there is a tendancy for any liquid being in a container to dissolve out some proportion of the elements constituting the container, whatever its material. Of course, it is in general a very low proportion, for example water contained in ordinary glass leaches out a proportion of Na.sup.2 O contained in this glass. A normalized test (DIN 1211) allows to compare the hydraulic resistance of glasses containing sodium and calcium (dissolution of 30 to 1000 .mu.g Na.sup.2 O per gr of glass reduced to powder, being in water of a temperature of 90.degree. C. during one hour).
This general phenomenon is to be taken into consideration in analytic chemistry and also in some divisions of high top chemistry, but not in general in everday life, except in very particular cases as with certain heavy metals like cadmium and lead where the tendancy for migration in materials used for kitchen ustensils or when they're coming into contact with liquid is well known. More particularly, crystal contains lead Monoxide (AFNOR Norm:NF 30004) and it has been noted that quantities, which can reach some ppm, can migrate towards acid liquids (pH about 3,5) conserved during quite a long time in container made of crystal.
Moreover, this phenomenon was the object of elaborate studies leading to the elaboration of control norms in order to "make sure the people are protected against the possible dangers caused by a contact of the food products with the surface of goods made of glass and employed for the preparation, service and conservation of food and drinks" (INTERNATIONAL NORM ISO 7086/1-1982).